Best perks

I have a question about the perks (suits abilities) if i can call them like that. What is the best 'perk' to spot enemies in the MP before they spot you? Or what is the best way not to be spotted (other then cloak)?

Either Tracker or Visor Enhance, the level 6 stealth upgrades. On let's you see foot steps and the other highlights enemies when looking down the sights. If you don't use stealth that much Nano-vision is a good bet.

Cloak and sprinting are the two best ways to avoid being seen, cloak being the better option.

They're called Suit Modules. Why can't anyone call the things in game by their actual name?! They always go back to COD or some crap. It's Specializations in Bad Company 2, Suit Modules in Crysis 2, Infantry Abilities in Homefront, and Perks in Call of Duty.